1. Field of the Invention
The present invention relates to a printing system and a method of controlling the same. More particularly, the present invention relates to a printing system and method for preventing printing errors due to a double fed paper medium.
2. Description of the Related Art
A printing system, such as a copying machine, an all-in-one machine and a laser printer, receives image data from a host through an interface such as a cable, so that image data can be printed on paper.
Such a printing system employs a printing process using an image forming apparatus by way of an example, wherein the image forming apparatus is connected to a Personal Computer (PC). In this case, a program file corresponding to a content to be printed out is read from the PC to input a printing instruction. Then, a printer driver is driven by the printing instruction. A user is allowed to designate a paper size for the paper to be printed on using the image forming apparatus through the printer driver. The printer driver receives image data and transmits the image data adjusted to a size corresponding to the designated size of the print medium to the image forming apparatus.
A control section of the image forming apparatus initiates printing based on the input image data. The size of a print medium fed from a paper tray is measured using a feeding sensor or the like. That is, the size of a print medium is determined by measuring the length of time until the feeding sensor detects the trailing edge of the print medium after the feeding sensor has detected the leading edge of the print medium. In addition, the control section determines whether the size of the print medium measured by the feeding sensor is the same as a preset print medium's size set by the printer driver, by comparing the measured size and the preset size.
If there is no difference between the values of compared sizes, image data is generated and printed according to the preset print medium's size set by the printer driver.
Whereas, if there is a difference between the values of compared sizes, the size of image data is adjusted based on the measured size of the print medium. As such, it is possible to prevent image data, which is larger than the measured size of the print medium, from being printed, whereby it is possible to prevent an image carrier or an image-transfer medium from being corrupted.
However, print mediums may sometimes be fed in an overlapped state as in the case of a double-feeding of paper. In such a case, the feeding sensor will recognize the print mediums as being larger than the real size thereof. Accordingly, the control section input with such information will readjust the size of image data based on the erroneously measured size of the print mediums. As a result, there is a problem in that even though print mediums with a normal size are fed, image data adjusted to a larger size may be printed on the print medium without correctly detecting such a situation.